DON’T view the Sun through sunglasses of any type or filters made from photographic film, or any combination of photographic filters, crossed polarisers or gelatin filters, CDs, CD-ROMs, or smoked glass. None of these are safe.

DO view the Sun through special filters made specifically for safe solar viewing. Ensure they are designed to be fitted securely to the kind of instrument you have. These include, e.g. aluminised Mylar filters, or black polymer filters, identified as suitable for direct viewing of the Sun, bearing the CE mark AND a statement that it conforms to European Community Directive 89/686/EEC.

DON’T fit any filter to a telescope without FIRST checking it thoroughly for damage. If it is scuffed, scratched, has pinholes in it, or you have any other doubts about it at all, DON’T use it.

Can I see the Transit of Mercury online?

The European Space Agency streamed the transit from a satellite so if you do not have equipment and cannot get to an event you can watch it through the here

So I missed it. When will it happen again?

Transits of Mercury are relatively rare events, with approximately 13 occurring every century in either November or May.

They occur in pairs, with the transit on May 9 being the first of the pair that will see its counterpart occur on 11th November 2019.

After 2019, we will have to wait until 13th November 2032 to see another Transit of Mercury.

Why is the Transit of Mercury important?

It was viewing the Transit of Mercury of 7 November 1677 that astronomer Edmond Halley realised that planetary transits could be used to measure the Earth’s distance from the Sun.

Today transits are still important in astronomy and are used as a method to detect exoplanets because the light from a star dips when a planet passes in front of it. From the size of the dip in luminosity, scientists can tell how large the planet is that is passing in front.